A number of information storage media have a predeterminable or calculable design lifetime or maximum usage. An example is flash memory which typically can support a number of memory erasure operations (such as in the range of about 10.sup.4 through about 10.sup.5 erasures) but which can be expected to fail some time after that number of erasures. Accordingly, the expected design lifetime of a flash memory is more a function of the manner in which it is used (and particularly, its erasure frequency) than the mere passage of time. To achieve a degree of confidence in the continued operation of a system which includes flash memory, the flash memory should be replaced as the number of erasure operations performed using the flash memory approaches the expected design lifetime of the flash memory. Accordingly, it would be useful to provide a system in which replacement of the flash memory (or similar data storage medium) will be encouraged, requested, and/or required at an appropriate time.
Although it would be possible to provide a system for manually providing a reminder of the need for a media replacement (such as marking reminder on a calendar) there is a significant risk that this type of reminder would become unassociated with the data storage medium. For example, if the data storage medium is a medium which is a removable medium (moved from one computer or other device to another computer or other device, a manual calendar reminder, for example, may not properly reflect the appropriate replacement date for the particular medium which is currently inserted in a computer (or other device). Furthermore, a manual reminder such as a calendar entry may be infeasible when design lifetime is based, not on date of installation, but on information that may not be readily available for, e.g., manual entry on a calendar, such as date of manufacture of the medium. Furthermore, when design lifetime is determined or affected by factors other than mere passage of time (such as number of erasures or similar usage factors) tracking such use dependent factors can be burdensome or infeasible for a manual reminder system. Accordingly, it would be useful to provide a system in which accurate and current design lifetime information, based on appropriate criteria, remain coupled, preferably physically coupled, to the memory medium or device.
Although, in a number of computing contexts, it may be possible to configure a computer to provide, or assist in providing, appropriate media replacement reminders, it can be disadvantageous to impose additional computing burden or "overhead" on a CPU (Central Processing Unit) for tracking usage of each storage medium and it can be burdensome to impose a programming or data entry burden on programmers or users. Accordingly, it would be useful to provide a system for encouraging or assuring appropriate storage medium replacement without substantially incurring or increasing computing, programming or data entry burden.
The type of response which is most appropriate, as the end-of-design-lifetime approaches, will vary depending on such factors as the type of medium involved and type of computing system or computing network where the device is employed and/or user preferences. In especially critical computing environments, it may be undesirable to give a user an opportunity to ignore or override a warning or request that media replacement is due. Accordingly, it would be useful to provide a system in which the system can be configured so as to respond in different fashions to the detection of an approaching end-of-design-lifetime event.